The present invention relates generally to hydrolyzate products of hydroxypropyl starch which are useful as low calorie bulking agents for use in substitutes for sucrose and other starch hydrolyzate products. More specifically, the invention relates to methods of removing off-flavor components from hydroxypropyl starch hydrolyzate products and improved products resulting therefrom.
Of interest to the present invention is the disclosure of Kesler et al., U.S. Pat. No. 3,505,110 which discloses low calorie sugar products prepared by hydrolysis of hydroxypropylated starch. Kesler discloses methods for preparing hydrolysis products of hydroxypropyl starch which are characterized by a DE of from 1 to 30 and are said to be composed principally of glucose and hydroxypropylated polysaccharides and contain little or no (preferably less than 0.5%) maltose. Kesler discloses what are characterized to be preferred methods for producing the hydrolyzate product comprising hydrolyzing hydroxypropyl starch with a liquefying enzyme to breakup the long chain starch molecules and then treating with a saccharifying enzyme to further hydrolyze the intermediate length molecules to produce glucose (having a degree of polymerization (DP of 1) to the substantial exclusion of maltose (DP 2). While the products of Kesler were characterized as being intended for use as substitutes for ordinary sugar, those products fail to be characterized by bulking properties suitable for use as a sucrose replacer in a wide variety of food products.
Quarles et al., U.S. Pat. No. 5,110,612, the disclosure of which is incorporated by reference, discloses the discovery that hydrolyzate products of hydroxypropyl starch, which comprise greater than about 15% by weight DP 2-6 hydrolyzate polymers and are characterized by a DE value of from about 20 to about 45, have bulking agent properties similar to those of sucrose. Quarles discloses that hydrolyzate products of hydroxypropyl starch produced by conventional acid and/or enzyme hydrolysis are generally unsuitable for use as sucrose substitutes unless they comprise greater than about 15% by weight DP 2-6 hydrolyzate polymers and a DE value greater than about 20. Quarles discloses that hydrolyzate products of hydroxypropylated starch having such elevated levels of "middle range" DP 2-6 starch polymers and accordingly reduced levels of DP 1 monomers and longer chain polymers (DP 7+) exhibit improved properties as food ingredients at any given DE value when compared with hydroxypropyl starch hydrolyzate products characterized by reduced levels of DP 2-6 starch polymers and elevated levels of DP 1 monomers and DP 7+ starch polymers.
Of interest to the present application is the fact that the hydroxypropyl starch hydrolyzate products of Quarles are characterized by a bitter off-flavor which renders those products undesirable for certain food applications.